Appearing before the king unsummoned could have meant death. Esther had not been invited by the king in 30 days

King Ahasuerus, who is thought to be Xerxes I, had a violent temper. Once, he ordered a man to be cut in half and displayed as a warning to others. He also removed Vashti as queen when she disobeyed him

Esther had to reveal that she was a Jewess and convince the king that he had been tricked by his trusted adviser